341
FXUS61 KOKX 301143
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
743 AM EDT Fri Aug 30 2024
.SYNOPSIS...
High pressure across New England will be slow to weaken and
retreat out into the Atlantic through tonight. A frontal system
approaches on Saturday, moving across the area Saturday night
into Sunday morning. A secondary cold front moves through late
Sunday into Sunday night. Thereafter, Canadian high pressure
builds in and will remain in control through at least the
middle of next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Main area of showers along with a few thunderstorms, oriented
from NW to SE across the Lower Hudson Valley, NE NJ and into
the NYC metro, has been overachieving with rainfall. Even with
CAPE values less than 500 J/kg, PWAT and lift associated with
shortwave have produced pockets of moderate to heavy rainfall.
MRMS 1hr accum rainfall in Passaic county NJ showed 0.75-1"
between 4 and 5 am. Latest radar imagery show this axis of
translating east at about 10 to 15kt. Expect weakening as it
works into the ridge axis across eastern areas the next couple
of hours.
The best forcing shifts east later this morning with ridging
aloft approaching from the west. This would favor decreasing
rain chances and confining any showers to western portions of
the forecast area. However, the latest HRRR continues to show
scattered showers into the afternoon and mainly across LI and
CT. There is really no support from any of the other CAMs. Thus,
prefer to play this down and stay with a drier forecast. In
fact, drier air may win out enough for sunshine across SE CT and
eastern LI.
Highs today are forecast to top out in the lower to mid 70s,
which is about 7 to 10 degrees below normal. This will be
accompanied by an easterly flow with high pressure retreating
off the New England coast and a stalled frontal boundary over
the Mid Atlantic states.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
Expect a mainly dry night with an upper level ridge moving
across the area. As winds gradually veer to the SE, there could
be some weak low-level warm advection producing drizzle and/or
sprinkles. For the time, have left the mention out of the
forecast. This would be mainly near the coast. Low tonight will
be in the 60s, but closer to normal with the cloud cover and
increasing low-level moisture.
On Saturday, the upper level ridge departs to the east while
low-level ridging gradually loses its grip of the area. A well
advertised amplifying upper trough across eastern Canada and
the Great Lakes sends a series of frontal systems toward the
area, the first of which will move across the area late Saturday
into Sunday morning. The associated cold front weakens as it
approaches and may even get hung up or wash out just east of the
area Sunday morning. The best forcing and instability with the
cold front will stay mainly north and west of the area. The
approaching warm front passes through Saturday evening with
little activity. That being said, still expect some moderate
showers, possibly a thunderstorm, mainly Saturday night into
Sunday morning. Rainfall amounts will average from 0.25 to 0.50"
across the area, highest from NYC and points north and west.
Isolated higher amounts are possible with any stronger convection.
The day 2 outlook from SPC places western portions of the area,
including SW CT, western LI, and points west under a marginal
to slight risk of severe weather. The main threat being isolated
damaging winds. Mid level winds do strengthen Saturday night,
but instability is very marginal.
Showers linger into the morning hours Sunday, especially across
eastern LI and SE CT. The question then is how much can the
airmass recover ahead of a secondary cold front approaching the
area Sunday night. Right now, there looks to be too much dry
air, thus limiting the instability. Have kept an isolated threat
for a shower and/or thunderstorm Sunday afternoon with a pre-
frontal tough.
Temperatures warm up Saturday into Sunday. Highs on Sunday with
a SW flow and 85H temps around 15C will get into the lower and
middle 80s. A few locations around the NYC metro may get as high
as the upper 80s. It will also be more humid during this time
with dew points around 70.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A secondary cold front moves through Sunday evening, so slight
chance PoPs linger into Sunday evening for eastern areas.
Thereafter, Canadian high pressure builds into the area and brings a
cool and dry airmass to the region, with sunny conditions. On
Monday, dewpoints drop into the 40s during the afternoon into
evening hours and will stay there through midweek. Temperatures
will be below normal for early September during most of next
week.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
High pressure across eastern Canada into coastal New England, and
the mid Atlantic will remain in place today as a surface trough
remains to the west.
Low confidence forecast with VFR conditions today, which may
become MVFR at times. There is a chance that MVFR prevails most
of the day, though this is looking less likely as dry air
moving in from the northeast associated with high pressure
becomes locked in place, until tonight at least. MVFR ceilings
move back into the area tonight.
Showers are moving into more stable air to the east this
morning and are expected to dissipate through the morning.
An easterly wind continues today, then shifts to the SE tonight
with winds speeds generally around 10 kt or less.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low confidence in ceiling forecast. However, MVFR conditions
look less likely during the day.
OUTLOOK FOR 12Z SUNDAY THROUGH TUESDAY...
Saturday: VFR. MVFR or lower possible in showers and
thunderstorms during the evening and overnight.
Sunday: Mainly VFR. Chance of showers, mainly in the morning.
Monday and Tuesday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Winds and waves will remain below SCA criteria through the
middle of next week. There could be a period of occasional 25 kt
gusts this weekend and on Monday with two cold frontal
passages, but this remains a low probability at this time.
&&
.HYDROLOGY...
Any hydro impacts over the weekend appear minimal at this time.
&&
.TIDES/COASTAL FLOODING...
The moderate risk of rip currents continues today with a
continued easterly flow. While winds will be a bit weaker, the
E to W sweep will enhance rip current activity along jetties and
groins.
On Saturday, the flow becomes southerly, just under 10 knots. 1 ft
long period southeasterly swell does build into the area, but
thinking low risk of rip currents for now with RCMOS showing
lowering probabilities into Saturday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JP/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...JP
AVIATION...JP
MARINE...JP/DW
HYDROLOGY...JP/DW
TIDES/COASTAL FLOODING...